Aluminum alkoxides find a wide variety of applications ranging from raw materials for producing ceramics to catalysts and reducing agents. Producing such, however, is not without its difficulties.
For instance, aluminum is extremely active and readily forms a self-passivating oxide with oxygen that, in turn, renders the material stable in air. This oxide forms a protective layer and precludes further reaction with the surrounding environment.
In order to break down this oxide layer so that continued oxidation can proceed, certain amalgams with aluminum have been suggested. In particular, mercury amalgams with aluminum have been used for this purpose. However, the use of mercury suffers from a number of disadvantages including the fact that mercury is toxic and undesirable from a safety and environmental viewpoint. Also, the solubility of aluminum in mercury is only about 2% to 3% by weight at normal room temperatures. This low solubility limits the reaction rate.
Another problem associated with reactions of aluminum and alcohols is that such reactions must compete with any available water vapor. The reactivity of water with aluminum is significantly faster than the reaction of aluminum with alcohols. In fact, according to the literature, aluminum is reported as being relatively unreactive with alcohols. For instance, see "Metal Alkoxides", Bradley, et al., Academic Press, 1978, pp. 11 and 12. According to Bradley, et al., aluminum metal requires the use of a catalyst for effective reaction of aluminum with an alcohol.
One such catalyst is suggested in Russian Pat. No. 742422 as being gallium for preparing aluminum C.sub.3 -C.sub.4 alcoholates by reacting at a temperature of 80.degree.-120.degree. C. This method suggested by Russian Pat. No. 742422 requires pre-treating the aluminum with mercury compounds as an activator.
In addition, gallium and gallium-indium alloys have been disclosed for the purpose of preventing the self passivation of an aluminum surface and to permit exposure of fresh aluminum to the environment.
In particular, U.S. Pat. No. 4,358,291 discloses dissolving aluminum in gallium or a gallium-indium alloy to thereby produce an amalgam whereby the aluminum will then react with the surrounding air environment. Continued dissolution of the aluminum into the gallium or gallium-indium prevents self passivation and permits continued oxidation of the aluminum. According to U.S. Pat. No. 4,358,291 reaction with water to produce pure Al.sub.2 O.sub.3 in conjunction with providing an energy source for heat and hydrogen is provided.
It has also been suggested to use aluminum dissolved in gallium or gallium-indium alloy for dehydration of liquid materials such as alcohols. See Cuomo, et al., "Dehydration via Gallium-Activated Aluminum", IBM Technical Disclosure Bulletin, Vol. 24, No. 2, July 1981, p. 1080.